Lecture 10

Question 1

how are membranes moved from ER to other cellular components?

Answer 1

Enzyme modification

Question 2

How can membranes change lipid composition?

Answer 2

enzyme modification to convert phospholipids

Question 3

How are Lipids exchanged between organelles?

Answer 3

lipid transfer proteins

Question 4

what do most Rough ER proteins become?

Answer 4

Glycoproteins

Question 5

what catalyzes sugar addition to oligosaccharide?

Answer 5

Glycosyltransferase

Question 6

what does the sugar arrangement on the oligosaccharide chains of glycoprotein depend on?

Answer 6

The spatial localization of enzymes

Question 7

what are some properties of misfolded proteins?

Answer 7

Glucose tagged, mannose deficient and degraded by proteasomes

Question 8

what does the accumulation of misfolded proteins trigger? How is it triggered? What occurs?

Answer 8

the unfolded protein response (UPR)

Occurs when BiP is prevented from inhibiting sensors

Sensors send signals to trigger proteins that destroy the misfolded proteins

Question 9

What is the first step for vesicular transport from the ER? What occurs?

Answer 9

The Golgi Complex

Transport vesicles fuse with one another forming the ERGIC (ER Golgi intermediate counterpart) towards the Golgi complex

Question 10

What is the Golgi complex composed of? What side faces where?

Answer 10

Stack of flattened cisternae

Cis Golgi side faces the ER

Trans Golgi side faces opposite side

Question 11

What is the Cis Golgi network responsible for?

Answer 11

Sort proteins for the ER or next Golgi station

Question 12

What is the trans side of the Golgi responsible for?

Answer 12

sorting proteins to the plasma membrane or intracellular destinations

Question 13

True for False
The Golgi Complex is uniform in composition

Answer 13

False

Question 14

What is used to carry materials between compartments?

Answer 14

Coated vesicles

Question 15

What are the 2 functions of protein coats?

Answer 15

Curves the membrane to form vesicles

Select the components to be carried by vesicles

Question 16

What are the 3 types of coated vesicle transport?

Answer 16

COPII, COPI and Clathrin

Question 17

Where does COPI move materials? what kind of materials?

Answer 17

from ERGIC and Golgi back towards the ER (or trans Golgi -> Cis Golgi)

movement of escaped proteins back to ER

Question 18

Where does COPII move materials? What does it bud off of? Where are the export signals from?

Answer 18

From the ER forwards to the ERGIC and Golgi complex

comes of the ER exit sites

Signals come from cytosolic tails of transported proteins

Question 19

Where does Clathrin move materials?

Answer 19

from the TGN to endosomes, lysosomes and vacuoles

Question 20

What do all vesicles have in common?

Answer 20

2 distinct layers; an outer and an inner

Question 21

What are the differences between the 3 Vesicle transporters?

Answer 21

Clathrin outer layer overlap extensively

COPII does no over lap and consists of 4 edges over 3

Question 22

What are COPI vesicles coat made of?

Answer 22

Coatamer, which is several proteins

Question 23

What are organelle proteins maintained by?

Answer 23

Retention of resident molecules by being excluded from transport

retrieval of escaped proteins back into their normal compartment

Question 24

How does escaped protein retrieval work?

Answer 24

specific receptors capture molecules, bring them to ER in COPI

Each membrane compartment has its own retrieval signal

Question 25

Describe the synthesis of Integral Membrane Proteins on ER-Bound
Ribosomes.
▪ Know the functions of the RER.
▪ Describe the structure and functions of the Golgi complex.
▪ Distinguish the functions of the different types of vesicle transport.